Hey,

Trying to find a replacement Smoke Alarm, currently have 2 of the EI166RC mains smoke alarms installed, I think the battery has started to go on one of them so need a replacement and as both alarms were fitted at the same time i assume it is not long before the other one has issues as well. Do i have any other options or am i looking at having to spend £100 on 2 of the Ei166e smoke alarms that as far as i am aware should use the same base as the EI166RC?

You can of course take both alarms off and re-use the wiring for a different brand at a better price. There are a number of suitable suppliers. If you just want to replace there are Ei166 replacement models.